13. Write a program in C++ using the concept of Data Abstraction and given specification 1) Create class Adder which has public and private access modifiers 2) Public access modifier has function addnum which has one parameter and will add number input from user with total; so total number 3) It also has a function called getTotal which will return the value of total 4) There is a constructor for class adder 5) Class adder has private variable called total 6) Create object of class adder and display the total obtained by calling function addnum